Correct optimization from 3464f5e77f34; add a test.
If there are two (or more) heads that point to the same .hgtags
node, we can safely skip parsing the file in all but the last head.
(In 3464f5e77f34, we were parsing the file in the first head and
skipping all the others.)
#!/bin/sh
hg init a
cd a
echo % new file
hg import -mnew - <<EOF
diff --git a/new b/new
new file mode 100644
index 0000000..7898192
--- /dev/null
+++ b/new
@@ -0,0 +1 @@
+a
EOF
echo % chmod +x
hg import -msetx - <<EOF
diff --git a/new b/new
old mode 100644
new mode 100755
EOF
test -x new || echo failed
echo % copy
hg import -mcopy - <<EOF
diff --git a/new b/copy
old mode 100755
new mode 100644
similarity index 100%
copy from new
copy to copy
diff --git a/new b/copyx
similarity index 100%
copy from new
copy to copyx
EOF
test -f copy -a ! -x copy || echo failed
test -x copyx || echo failed
cat copy
hg cat copy
echo % rename
hg import -mrename - <<EOF
diff --git a/copy b/rename
similarity index 100%
rename from copy
rename to rename
EOF
hg locate
echo % delete
hg import -mdelete - <<EOF
diff --git a/copyx b/copyx
deleted file mode 100755
index 7898192..0000000
--- a/copyx
+++ /dev/null
@@ -1 +0,0 @@
-a
EOF
hg locate
test -f copyx && echo failed || true
echo % regular diff
hg import -mregular - <<EOF
diff --git a/rename b/rename
index 7898192..72e1fe3 100644
--- a/rename
+++ b/rename
@@ -1 +1,5 @@
a
+a
+a
+a
+a
EOF
echo % copy and modify
hg import -mcopymod - <<EOF
diff --git a/rename b/copy2
similarity index 80%
copy from rename
copy to copy2
index 72e1fe3..b53c148 100644
--- a/rename
+++ b/copy2
@@ -1,5 +1,5 @@
a
a
-a
+b
a
a
EOF
hg cat copy2
echo % rename and modify
hg import -mrenamemod - <<EOF
diff --git a/copy2 b/rename2
similarity index 80%
rename from copy2
rename to rename2
index b53c148..8f81e29 100644
--- a/copy2
+++ b/rename2
@@ -1,5 +1,5 @@
a
a
b
-a
+c
a
EOF
hg locate copy2
hg cat rename2